When blending an imported object with its new background, matching shadows is a big challenge. You need to create a series of shadows that correspond to the background image’s surfaces and light source(s). Using Layer Masks to accomplish this gives you a lot of creative freedom and makes the process easier than you may think.

To create realistic shadows, we’ll show you how to:

•Inspect an image to understand its light source(s) and types of shadows an imported object requires.

•Create a simple drop shadow that falls on another object in the background image and position it for easy editing.

•Edit and fine-tune the drop shadow with a Layer Mask and Brush tool so it suits your image.

•Create shadows for each additional surface, as well as the imported object itself, to give your new image a finished, realistic look.

Objects rarely cast a single shadow. For a realistic effect, you often need to create a series of shadows that fall on multiple surfaces, as shown in Figure A. Doing so requires that you have a good understanding of the light source in your original image, as well as the techniques to create and manipulate shadows. We’ll show you how to do all that in this article.

A

Understand your shadows

To begin, open the image you want to use as your background and inspect the shadows that appear in it. This helps you decide how to create the shadows for an object you want to import. If you’re using an outdoor background image, the following aspects will tell you something about the angle of your light source (the sun).

•Time of day: At solar noon, the sun is at the highest point in the sky and your shadows will be short and dark. Both dawn and dusk have longer, more muted shadows.

•Season: The sun is lowest and shadows are longest in winter. Summer has the shortest shadows, while fall and spring have less extreme shadow lengths.

•Latitude: Unless you’re in the tropics, the farther you get away from the equator, the lower the sun appears in the sky on any given day.

In addition to the angle of your light source, the type of light you have is also vital to the type of shadows you’ll have.

•Natural light: Outdoor lighting is affected by cloudiness and the weather in general. (Even a thin veil of cloud cover will drastically effect how harsh and defined a shadow is.)

Shadow Tip: Pay attention to how different light sources and conditions affect shadows around you throughout the day—it will greatly improve your ability to recreate realistic shadows in your designs.

Import an object into your background image

To get started with this technique, you’ll need some sort of image to use as a background, and then you’ll need an image containing an object that you wish to add to your background image and cast a shadow from. If you want to follow along with our example, download the file shadows.zip from the URL listed at the beginning of this article, and extract the files fence.psd and dog.psd. (Images provided by PhotoSpin. Some images modified for educational purposes.)

1.Open both downloaded files in Photoshop.

Note: The file dog.psd has a transparent background. If you’re using another image, you’ll need to isolate the object from the rest of the image (using a selection tool such as the Polygonal Lasso tool or the Magic Wand tool) and put it on its own layer.

2.Select the Move tool move and drag the Dog layer from the dog.psd file into the fence.psd document. Doing so automatically places the dog on its own layer in the fence.psd file.

•Will parts of a shadow break across a surface such as fence or railing?

•How will the angle/location of each surface affect the shadow(s)?

Add the first shadow

Although the order in which you create your shadows doesn’t matter, we’ll start out with the easiest one—the shadow that breaks across the fence. First, we’ll create the shadow, then we’ll transform it.

To create the first shadow:

1.Select the Dog layer to make it active.

2.Click on the Add A Layer Style button add_layer_style at the base of the Layers palette.

3.Select Drop Shadow from the Add A Layer Style pop-up menu.

4.Click and drag the drop shadow of the dog into place, as illustrated in Figure B, until you have it roughly where you think it should be.

5.Leave the other drop shadow settings at their defaults, and click OK in the Drop Shadow dialog box.

6.[control]-Click (right-click in Windows) on the drop shadow effect in the Layers palette.

7.Choose Create Layer from the shortcut menu and click OK in the warning box to disregard the warning.

8.Rename the new shadow layer First Drop Shadow.

To transform the shadow:

1.Select the First Drop Shadow layer in the Layers Palette to make it active.

3.Press and hold down [shift] as you drag any corner of the bounding box toward the center to shrink your shadow proportionately.

Shadow Tip: The amount you need to adjust your shadow size varies according to both the angle of the light and the distance between the object casting the shadow and the surface it is being cast upon. If you have a low angle light source, you’ll need to enlarge, rather than shrink, your shadow.

4.Double-click anywhere within the bounding box when you’re satisfied to accept the transformation.